Data communication networks may include various computers, servers, nodes, routers, switches, hubs, proxies, and other devices coupled to and configured to pass data to one another. These devices are referred to herein as “network elements,” and may provide a variety of network resources on a network. Data is communicated through data communication networks by passing protocol data units (such as packets, cells, frames, or segments) between the network elements over communication links on the network. A particular protocol data unit may be handled by multiple network elements and cross multiple communication links as it travels between its source and its destination over the network. Hosts such as computers, telephones, cellular telephones, Personal Digital Assistants, and other types of consumer electronics connect to and transmit/receive data over the communication network and, hence, are users of the communication services offered by the communication network.
One particular type of network element is referred to herein as a packet switching device such as a data switch or a router. A packet switching device receives data at a particular port, and outputs the data at one or more other ports onto other links on the network. A typical analysis of a packet switching device will look at a number of packets forwarded, a number of packets dropped, and an average latency (a measurement of how long it takes a packet to traverse a packet switching device). The commercial practice is to provide details on forwarding rates, loss rates, and latency.